U.S. patent number 5,745,040 [Application Number 08/740,023] was granted by the patent office on 1998-04-28 for outdoor alerting device for smoke alarms.
Invention is credited to Lisa M. Loughridge.
United States Patent |
5,745,040 |
Loughridge |
April 28, 1998 |
Outdoor alerting device for smoke alarms
Abstract
An outdoor alerting device for smoke alarms including an alarm
detecting and alerting device drive unit and an exterior alerting
device including a loudspeaker installed within a housing and a
light display unit attached to the housing and having a light bulb.
The alarm detecting and alerting device drive unit includes an
alarm detection circuit including a microphone having a microphone
output in electrical connection with an amplifier circuit for
converting the audible alarm into an amplified electrical
microphone signal. The amplified electrical microphone signal is
then passed through a band pass filter that is tuned to the main
audible output frequency of the audible alarm of the smoke detector
to produce a filtered microphone signal. The filtered microphone
signal is the passed through a rectifier circuit to convert the
filtered microphone signal into a DC microphone signal. The DC
microphone signal is then output to the signal input of a
comparator. The reference input of the comparator is supplied with
a predetermined reference voltage such as through a voltage divider
circuit. The output of the comparator is used to trigger the
exterior alerting device after being passed through a delay
network.
Inventors: |
Loughridge; Lisa M. (Portage,
IN) |
Family
ID: |
24974729 |
Appl.
No.: |
08/740,023 |
Filed: |
October 23, 1996 |
Current U.S.
Class: |
340/628; 340/584;
340/691.5; 340/693.1; 367/199; 381/56 |
Current CPC
Class: |
G08B
1/08 (20130101); G08B 7/064 (20130101); G08B
17/00 (20130101) |
Current International
Class: |
G08B
7/00 (20060101); G08B 7/06 (20060101); G08B
1/00 (20060101); G08B 1/08 (20060101); G08B
5/22 (20060101); G08B 5/36 (20060101); G08B
017/10 () |
Field of
Search: |
;340/539,577-579,584,628-630,691-693 ;367/197-199 ;381/56-58 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hofsass; Jeffey
Assistant Examiner: Wu; Daniel J.
Attorney, Agent or Firm: Breaux; Joseph N.
Claims
What is claimed is:
1. An outdoor alerting device for smoke alarms comprising:
an alarm detecting and alerting device drive unit having a alarm
detecting circuit for detecting an audible alarm from a smoke
detector; and
an exterior alerting device including a housing having an audible
noise generating mechanism installed within a compartment formed
within said housing, and a visual attraction mechanism in
connection with said housing, said audible noise generating
mechanism and said visual attraction mechanism being responsive to
a signal from said alarm defecting and alerting device drive
unit;
said alarm detecting circuit including:
a microphone,
an amplifier circuit,
a band pass filter,
a rectifier circuit,
a comparator including a reference voltage generating network,
a first retriggerable monostable multi-vibrator, and
a first OR logic gate;
said microphone having a microphone output in electrical connection
with an amplifier input of said amplifier circuit;
said amplifier circuit having an amplifier output in electrical
connection with a filter input of said band pass filter;
said band pass filter having a filter output in electrical
connection with a rectifier input of said rectifier circuit;
said rectifier circuit having a rectifier output in electrical
connection with a signal input of said comparator;
said reference voltage generating network having a reference
voltage output in electrical connection with a reference voltage
input of said comparator;
said comparator having a comparator output in electrical connection
with a first trigger input of said first retriggerable monostable
multi-vibrator and a first OR gate input of said first OR logic
gate; and
said first retriggerable monostable multi-vibrator having a first
multi-vibrator output in electrical connection with a second OR
gate input of said first OR logic gate.
2. The outdoor alerting device for smoke alarms of claim 1
wherein:
said alarm detecting circuit further includes:
a first non-retriggerable monostable multi-vibrator;
a delay network;
an AND logic gate; and
a second non-retriggerable, resettable, monostable multi-vibrator;
and wherein:
an OR gate output of said first OR logic gate is electrically
connected to a delay input of said delay network and a second
trigger input of said first non-retriggerable, monostable
multi-vibrator;
a delay output of said delay network is electrically connected to a
first AND gate input of said first AND logic gate; and
a second multi-vibrator output of said non-retriggerable,
monostable multi-vibrator is electrically connected to a second AND
gate input of said AND logic gate.
3. The outdoor alerting device for smoke alarms of claim 2
wherein:
said AND logic gate has an AND gate output in electrical connection
with a third trigger input of a second non-retriggerable,
resettable, monostable multi-vibrator; and
said second non-retriggerable, resettable, monostable
multi-vibrator has a third multi-vibrator output in electrical
connection with a power relay.
4. The outdoor alerting device for smoke alarms of claim 3
wherein:
said second non-retriggerable, resettable, monostable
multi-vibrator has a reset input; and
said alarm detecting circuit further includes a momentary contact
switch in electrical connection with said reset input.
5. The outdoor alerting device for smoke alarms of claim 1
wherein:
a pass band of said band pass filter is selected to be the
bandwidth at which the greatest audible power is output from a
smoke detector speaker.
6. The outdoor alerting device for smoke alarms of claim 5,
wherein:
said alarm detecting circuit further includes:
a first non-retriggerable monostable multi-vibrator;
a delay network;
an AND logic gate; and
a second non-retriggerable, resettable, monostable multi-vibrator;
and wherein:
an OR gate output of said first OR logic gate is electrically
connected to a delay input of said delay network and a second
trigger input of said first non-retriggerable, monostable
multi-vibrator;
a delay output of said delay network is electrically connected to a
first AND gate input of said first AND logic gate; and
a second multi-vibrator output of said non-retriggerable,
monostable multi-vibrator is electrically connected to a second AND
gate input of said AND logic gate.
7. The outdoor alerting device for smoke alarms of claim 6
wherein:
said AND logic gate has an AND gate output in electrical connection
with a third trigger input of a second non-retriggerable,
resettable, monostable multi-vibrator; and
said second non-retriggerable, resettable, monostable
multi-vibrator has a third multi-vibrator output in electrical
connection with a power relay.
8. The outdoor alerting device for smoke alarms of claim 7
wherein:
said second non-retriggerable, resettable, monostable
multi-vibrator has a reset input; and
said alarm detecting circuit further includes a momentary contact
switch in electrical connection with said reset input.
Description
TECHNICAL FIELD
The present invention relates to alerting devices and more
particularly to an outdoor alerting device triggered by a smoke
alarm having a mechanism for detecting activation of a smoke alarm
within a building and an outdoor alerting device including an
audible and a visual alerting mechanism for alerting individuals
outside of a building when a smoke alarm within a building has been
activated.
BACKGROUND OF THE INVENTION
Conventional smoke detecting devices typically have an audible
alarm to warn the occupants of the building when a smoke alarm has
been activated within the building. Although these alarms work fine
to alert the occupants of the building, individuals outside of the
building are often unable to detect the audible alarm output of the
smoke detector and provide assistance to the occupants of the
building. It would be desirable, therefore, to have an alerting
device that could be triggered by a smoke detector within a
building that would provide an audible and visual alerting
mechanism exteriorly of the building to alert individuals outside
of the building to an alarm condition within the building. This
would be particularly useful in situations where a pot has been
unattended on a stove by an individual who has stepped outside the
building and then been distracted.
Because, it can be expensive to wire such an alerting device to one
or more of the smoke detectors within a building it would be
further desirable to have an outdoor alerting device that was
triggered by a triggering circuit having detecting mechanism
positionable within the building for detecting the presence of an
audible alarm signal from any of the smoke detectors within the
building. Also to prevent unduly arming neighbors and other
individuals, it would be a further benefit to have such a
triggering mechanism that included a delay mechanism for providing
a predetermined delay period between detecting the presence of an
audible alarm from a smoke detector and triggering the outdoor
audio and visual alerting devices.
SUMMARY OF THE INVENTION
It is thus an object of the invention to provide an outdoor
alerting device for smoke alarms that is triggered by a smoke
detector within a building that provides an audible and visual
alerting mechanism exteriorly of the building.
It is a further object of the invention to provide an outdoor
alerting device for smoke alarms that is triggered by a triggering
circuit having a detecting mechanism positionable within the
building that detects the presence of an audible alarm signal from
a smoke detector.
It is a still further object of the invention to provide an outdoor
alerting device for smoke alarms that detects the presence of an
audible alarm signal from a smoke detector that includes a delay
mechanism for delaying activation of the outdoor alerting device
for a predetermined period of time after detecting the presence of
an audible alarm from a smoke detector.
It is a still further object of the invention to provide an outdoor
alerting device for smoke alarms that accomplishes all or some of
the above objects in combination.
Accordingly, an outdoor alerting device for smoke alarms is
provided. The alerting device for smoke alarms includes an alarm
detecting and alerting device drive unit and an exterior alerting
device including an audible noise generating mechanism such as a
loudspeaker installed within a housing and a light display unit
attached to the housing and having a light bulb or other visual
attraction mechanism installed therein. The alarm detecting and
alerting device drive unit includes an alarm detection circuit
including a microphone having a microphone output in electrical
connection with an amplifier circuit for converting the audible
alarm into an amplified electrical microphone signal. The amplified
electrical microphone signal is then passed through a band pass
filter that is tuned to the main audible output frequency of the
audible alarm of the smoke detector to produce a filtered
microphone signal. The filtered microphone signal is the passed
through a rectifier circuit to convert the filtered microphone
signal into a DC microphone signal. The DC microphone signal is
then output to the signal input of a comparator. The reference
input of the comparator is supplied with a predetermined reference
voltage such as through a voltage divider circuit. The output of
the comparator is then split and fed simultaneously into a first
input of a first OR logic gate and the trigger input of a first
retriggerable monostable multi-vibrator having a stable output
period of a first predetermined length. The output of the first
retriggerable monostable multi-vibrator is fed into a second input
of the first OR logic gate. The output from the first OR logic gate
is then split. One line from the output of the first OR gate is fed
into the trigger input of a first non-retriggerable monostable
multi-vibrator having a stable output period of a second
predetermined length that is at least three times greater than the
first predetermined length. The other line from the output of the
first OR logic gate is fed into a delay network having a delay time
between the input to the delay network and the output of the delay
network that is greater than the time required for the first
non-retriggerable monostable multi-vibrator to change output state
at the complimentary output thereof and stabilize. The output of
the delay network and the complementary output of the first
non-retriggerable monostable multi-vibrator are then fed into
separate inputs of an AND logic gate and the output of the AND
logic gate fed into the trigger input of a second
non-retriggerable, resettable, monostable multi-vibrator having a
stable output period of a third predetermined length equal to the
desired automatic reset period for the outdoor alerting device. The
output of the second non-retriggerable, resettable, monostable
multi-vibrator is fed to the control input of a power relay. The
contacts of the power relay are wired in series between the speaker
and the light bulb of the audible and visual alerting device. A
momentary contact switch is wired to a reset input of the second
non-retriggerable, resettable monostable multi-vibrator to allow
the user to reset the alarm detecting and alerting device drive
unit when desired.
In use the microphone detects audible noise and converts the
audible noise into an electrical signal. The electrical signal is
amplified and then fed through a band pass filter that strips of
all but the signal corresponding to the frequency of the smoke
detector alarm. The filtered signal is then converted into a DC
voltage and then compared to a reference voltage by the comparator.
If the comparator detects a signal voltage that is greater than the
reference voltage then the circuit has detected that an audible
smoke detector alarm is sounding. The reference voltage can be
preset during manufacture of the circuit or an adjustable resister
can be placed in the voltage divider circuit generating the
reference voltage to allow the user to set the reference voltage
after installation.
The first retriggerable monostable multi-vibrator and the first OR
logic gate are used to filter out small interruptions in the output
of the comparator that can be caused by for instance a fluctuating
audible alarm output from the smoke detector or other source. The
first non-retriggerable monostable multi-vibrator is used to
provide the delay between detecting the audible alarm output from
the smoke detector and triggering the outdoor alerting device. If
the output from the OR logic gate remains at a high voltage longer
than the second predetermined length of time than the alarm
alerting device is triggered. The delay network is provided to
assure that the complementary output of the first non-retriggerable
monostable multi-vibrator has had a chance to change state and
become stable at the input to the AND logic gate before the output
from the OR logic gate is applied to the other input of the AND
logic gate. Once the output from the AND logic gate goes high, the
first non-retriggerable, resettable monostable multi-vibrator is
triggered closing the power relay for a third preset length of
time. This length of time is selected to be the desired outdoor
alerting period before automatic reset. The automatic reset is
provided to minimize undesirable long periods of operation that may
be generated by a false alarm.
BRIEF DESCRIPTION OF DRAWINGS
For a further understanding of the nature and objects of the
present invention, reference should be had to the following
detailed description, taken in conjunction with the accompanying
drawings, in which like elements are given the same or analogous
reference numbers and wherein:
FIG. 1 is a plan view of an exemplary embodiment of the outdoor
alerting device for smoke alarms of the present invention showing
the alarm detecting and alerting device drive unit and the exterior
alerting device including a loudspeaker installed within a housing
and a light display unit extending from the housing.
FIG. 2 is a schematic diagram showing a representative optional
hard wired installation.
FIG. 3 is a schematic diagram of an exemplary alarm detecting and
alerting device drive circuit.
DESCRIPTION OF THE EXEMPLARY EMBODIMENT
FIG. 1 shows an exemplary embodiment of the outdoor alerting device
for smoke alarms of the present invention generally designated by
the numeral 10. Alerting device 10 includes an alarm detecting and
alerting device drive unit, generally designated by the numeral 12,
and an exterior alerting device, generally designated by the
numeral 14. In this embodiment, exterior alerting device 14
includes a metal housing 15 having a loudspeaker grating 16 having
a conventional loudspeaker 18 installed there behind within a
compartment 20 formed within housing 15. A light display unit,
generally designated 22, is attached to a bottom surface of housing
15 and includes a transparent dome 24 defining a bulb compartment
having a light bulb 26 disposed therein. Light bulb 26 and
loudspeaker 18 are each connected to alarm detecting and alerting
device drive unit 14 through an electrical cable 28 running between
housing 15 and a drive unit housing 30. Drive unit housing 30
houses an alarm detecting and alerting device drive unit
circuit.
FIG. 2 shows a schematic diagram of an exemplary alarm detecting
and alerting device drive unit circuit generally designated by the
numeral 32. Alarm detecting and alerting device drive unit circuit
32 includes a microphone 34; an amplifier circuit 36; a band pass
filter 38; a rectifier circuit 40; a comparator 42 including a
reference voltage generating network 44; a first retriggerable
monostable multi-vibrator 48; a first OR logic gate 50; a first
non-retriggerable monostable multi-vibrator 52; a delay network 54;
an AND logic gate 56; a second non-retriggerable, resettable,
monostable multi-vibrator 58; a first light emitting diode 60; a
momentary contact switch 62, a terminal block 64; and a power relay
66. Also shown schematically in the figure are loudspeaker 18 and
light bulb 26.
Microphone 34 is a conventional microphone having a microphone
output 70 in electrical connection with an amplifier input 72 of a
conventional amplifier circuit 36. An amplifier output 74 of
amplifier circuit 36 is in electrical connection with a filter
input 76 of a conventional band pass filter 38. The pass band of
band pass filter 38 is selected to be the bandwidth at which the
greatest audible power is output from the smoke detector
speaker.
A filter output 78 of band pass filter 38 is in electrical
connection with a rectifier input 80 of a conventional rectifier
circuit 40. Rectifier circuit 40 can be either a half-wave or a
full wave rectifier. A rectifier output 82 of rectifier circuit 40
is in electrical connection with a signal input 84 of conventional
comparator 42. In this embodiment, reference voltage generating
network 44 is a conventional resistance voltage dividing network.
The reference voltage output 85 generated by reference voltage
generating network 44 is electrically connected to a reference
voltage input 86 of comparator 42.
The comparator output 88 of comparator 42 is in electrical
connection with a trigger input 90 of first retriggerable
monostable multi-vibrator 48 and a first OR gate input 92 of first
OR logic gate 50. First retriggerable monostable multi-vibrator 48
and first OR logic gate 50 are conventional integrated circuits. In
this embodiment the stable output period first retriggerable
monostable multi-vibrator 48 is preset to a first predetermined
length of about one second. The multi-vibrator output 94 of first
retriggerable monostable multi-vibrator 48 is electrically
connected to a second OR gate input 95 of first OR logic gate
50.
The OR gate output 96 of first OR logic gate 50 is electrically
connected to the delay input 100 of delay network 54 and the
trigger input 102 of non-retriggerable, monostable multi-vibrator
52. Also connected to OR gate output 96 is a conventional wiring
terminal block 64. Wiring terminal block 64 is utilized when it is
desired to hard wire alarm detecting and alerting device drive unit
circuit 32 to the alarm output of a smoke detector which will
maintain OR gate output 96 at a high level even when the voltage
level of signal input 92 is less than the voltage level of
reference input 95. FIG. 3 shows an illustration of such an
installation with a cable 67 run between terminal block 64 and an
alarm output 69 of a conventional smoke detector 71.
Referring back to FIG. 2, the delay output 104 of delay network 54
is electrically connected to a first AND gate input 106 of first
AND logic gate 56. The multi-vibrator output 108 of
non-retriggerable, monostable multi-vibrator 52 is electrically
connected to a second AND gate input 110 of AND logic gate 56. The
stable output period of non-retriggerable, monostable
multi-vibrator 52 is set for a predetermined length of about sixty
seconds. Non-retriggerable, monostable multi-vibrator 52 and AND
logic gate 56 are conventional integrated circuits.
The AND gate output 112 of AND logic gate 56 is electrically
connected to the trigger input 114 of second non-retriggerable,
resettable, monostable multi-vibrator 58. Second non-retriggerable,
resettable, monostable multi-vibrator 58 is a conventional
integrated circuit.
The multi-vibrator output 120 of second non-retriggerable,
resettable, monostable multi-vibrator 58 is electrically connected
to a first diode lead 118 of light emitting diode 60 and the
control input 119 of a power relay 66. The stable output period of
second non-retriggerable, resettable, monostable multi-vibrator 58
is set at about fifteen minutes. Light emitting diode 60 and power
relay 66 are conventional components. Momentary contact switch 62
is a conventional momentary contact switch that is wired to the
reset input 124 of second non-retriggerable, resettable, monostable
multi-vibrator 58. Depressing momentary contact switch 62 causes
second non-retriggerable, resettable, monostable multi-vibrator 58
to be reset. Closure of the contacts of power relay 66 energizes
light bulb 26 and loudspeaker 18.
With general reference to FIGS. 1-3, alerting device 10 is
installed by installing alarm detecting and alerting device drive
unit 12 in a convenient location within the building and installing
exterior alerting device 14 outside of the building under eve or
other convenient location where light bulb 26 can attract attention
when illuminated. Operation of alerting device 10 is as previously
described.
It can be seen from the preceding description that an outdoor
alerting device for smoke alarms has been provided that is
triggered by a smoke detector within a building; that provides an
audible and visual alerting mechanism exteriorly of the building;
that is triggered by a triggering circuit having a detecting
mechanism positionable within the building that detects the
presence of an audible alarm signal from a smoke detector; and that
includes a delay mechanism for delaying activation of the outdoor
alerting device for a predetermined period of time after detecting
the presence of an audible alarm from a smoke detector.
It is noted that the embodiment of the outdoor alerting device for
smoke alarms described herein in detail for exemplary purposes is
of course subject to many different variations in structure,
design, application and methodology. Because many varying and
different embodiments may be made within the scope of the inventive
concept(s) herein taught, and because many modifications may be
made in the embodiment herein detailed in accordance with the
descriptive requirements of the law, it is to be understood that
the details herein are to be interpreted as illustrative and not in
a limiting sense.
* * * * *